Notes on recovery attempt of Chiq (Changhong) L40H7A TV stuck after boot on blue loading circle animation

Problem description

Device is powered on
Device shows white "Android" text and shortly after colorful full-screen animation
Background turns black and a 3/4 (three qarter) blue circle that is rotating is displayed
This continues for over 10 hours, powercycles etc do not change this and we always end up with this animation

Open Changhong service website: https://aftersales.changhong.cz/firmwaresearch/
Enter serial number of your device to be shown relevant downloads
- Manuals
- Technical drawings
- .rar file (that is actually a zip file) with product information
- upgrade_loader_no_tvcertificate_no_tvconfig.zip file which contains the .pkg with the update
- Extract the .zip file to get access to the .pkg file within
Create an empty FAT32 formatted USB thumbdrive
- sudo wipefs -a /dev/sdX (make sure to use the correct device!)
- sudo mkfs.vfat -F 32 /dev/sdX
- Mount the drive
- Copy the .pkg file (useing the exact filename it had after extraction) to the root of the mounted thumbdrive
- Make sure the copy is complete (e.g., by calling sync)
- unmount the drive
Remove USB thumbdrive
Power off TV (unplug)
Plug USB drive into back of the TV, reconnect and power on TV
wait
You should be greeted by a blue screen with text and a loading bar
wait
The screen will switch 3-4x times to a different blue loading display
wait
The TV should reboot and show the Chiq logo as well as the colorful loading animation
- This is shown significantly longer than usual, wait
You might see a settings menu for language selection etc, DO NOT do anything, wait
- The device will reset itself once more
You should be good to go